Prospect and Challenges of Hydrate-Based Hydrogen Storage in the Low-Carbon Future

Abstract

Hydrogen hydrate is a promising material for safe and potentially cost-effective hydrogen storage. In particular, hydrogen hydrate has potential for applications in large-scale stationary energy storage to dampen the temporal variation of renewable energy, for example, in the form of hydrogen-ready gas-fired power plants for generating energy when the renewable power is not available. Preliminary SWOT (strengths, weaknesses, opportunities, threats) analysis indicates that such hydrate-based hydrogen storage (HBHS) has intrinsic competitive edges. However, while the theoretical hydrogen density of the hydrate could reach ∼5 wt %, experiments have not achieved such a high hydrogen storage capacity under practical conditions. This low gravimetric hydrogen density, plus the slow kinetics of hydrogen inclusion in the hydrate, presents an outstanding challenge for commercializing the HBHS. Future research is urged to resolve both the gaps in knowledge and technological barriers for realizing this unconventional technology. Particular future directions include the elucidation of the working mechanism of hydrate promoters, rational designs of new promoters, upscaled experiments and demonstrations, the assessment of long-term stability of hydrogen hydrates, and systematic SWOT analysis. This paper offers an insightful view of the HBHS in low-emission economies.